When manufacturing an electronic device, a plasma processing such as a plasma etching or the like is performed with respect to a workpiece. In this plasma processing, in-plane uniformity is required in processing the workpiece. In order to realize the in-plane uniformity of the processing, it is required to accurately control a temperature distribution of the workpiece.
A system which adjusts a temperature of a mounting stand to control the temperature distribution of the workpiece has been used. For example, a system in which a temperature of an electrostatic chuck of a mounting stand is controlled by supplying a high-temperature fluid and a low-temperature fluid to a temperature adjusting unit is available. The temperature adjusting unit is formed within the mounting stand to extend along a circumferential direction of the mounting stand. Such a system includes a bypass flow path, a low-temperature flow path and a high-temperature flow path. The bypass flow path is connected to an inlet and an outlet of the temperature adjusting unit and circulates a fluid between the inlet and the outlet. The low-temperature flow path is connected to the bypass flow path and supplies a low-temperature fluid provided from a low-temperature-side temperature adjusting unit to the bypass flow path. The high-temperature flow path is connected to the bypass flow path and supplies a high-temperature fluid provided from a high-temperature-side temperature adjusting unit to the bypass flow path. Valves whose valve opening degrees are changed in conjunction with each other are respectively connected to the bypass flow path, the low-temperature flow path and the high-temperature flow path.
Furthermore, there is available a temperature control device which includes a mounting stand, a chiller unit, a heating unit, a flow path switching unit, a controller, and so forth. In the mounting stand, there are formed a first coolant path which extends along a circumferential direction of the mounting stand in the central region of the mounting stand and a second coolant path which extends along the circumferential direction of the mounting stand in a peripheral region of the mounting stand. By operating the heating unit and switching an opening/closing of an on-off valve of the flow path switching unit under the control of the controller, the temperature control unit individually controls temperatures of coolants flowing through the first coolant path and the second coolant path of the mounting stand through the use of a single chiller unit.
In the device (or the system) mentioned above, a flow path which allows a heat exchange medium to flow therethrough is formed along the circumferential direction of the mounting stand. In this device, the heat exchange medium receives heat from a substrate during the course of flowing through the flow path. This causes a difference in temperature of the heat exchange medium flowing through the flow path, depending on positions in the circumferential route. As a result, a difference is generated in a temperature distribution of the mounting stand, which makes it difficult to accurately control the temperature of the mounting stand.